Dogging device for saw mills



Nov. 15, 1955 J, H. MARSH 2,723,690

DOGGING DEVICE FOR SAW MILLS Filed Nov. 25, 1953 James H. Marsh IN V EN TOR.

Mun 5% United States Patent DOGGING DEVICE FOR SAW MILLS James H. Marsh, Grangeville, Idaho Application November 23, 1953, Serial No. 393,566

1 Claim. (Cl. 143-125) The present invention relates to new and useful improvements in saw mill equipment, and more particularly to a dogging device to hold a log in sawing position on the head block of the saw mill carriage.

An important object of the invention is to provide a secondary log holding dog to cooperate with the primary dog to effectively hold the log in position on the saw carriage.

Another object of the invention is to provide fluid or air pressure operating means to swing the secondary dog into and out of log engaging position.

A still further object is to provide a device of this character of simple and practical construction, which is eflicient and reliable in operation, relatively inexpensive to manufacture and install in operative position on the saw machine, and which is otherwise well adapted for the purpose for which the same is intended.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure 1 is a transverse sectional view of the head block of a saw mill and showing the secondary dogging device mounted in position thereof; and

Figure 2 is an enlarged perspective view of the secondary dog.

Referring now to the drawing in detail wherein for the purpose of illustration I have disclosed a preferred embodiment of my invention, the numeral 5 designates a head block of a saw mill on which a log 7 is supported against the knees 6. A guard arm 8 is attached to and extends upwardly adjacent the vertical face 9 of each knee 6 and the upper end of arm 8 is inclined rearwardly, as indicated at 10.

The secondary dog arm is shown at 11, and is provided adjacent its rear end with laterally projecting bearings 12 to pivotally support the arm on a pin 13 which is attached to the knee 6. The front end of the arm 11 extends downwardly and forwardly under the log 7 and is provided with one or more teeth 14 which may be welded to or integrally formed with the arm and extend upwardly for biting into the underside of the log.

A piston rod 15 is pivoted to the rear end of arm 11 and extends upwardly into a cylinder 16 provided with a piston 17 attached to the piston arm 15. The upper end of cylinder 16 is pivoted to a bracket 18 attached to the upper end of guard arm 8.

The cylinder 16 is of a double-acting type with hose lines 19 and 20 attached adjacent the respective ends of the cylinder and connected to a suitable source of air, steam or other fluid pressure to oppositely actuate the piston 17 and swing the dogging arm 11 into and out of engagement with the log 7.

The secondary dogging arm 11 is used in conjunction with the usual primary dogging device (not shown) which forms part of the conventional equipment of a saw mill to engage the top of the log for holding the latter on the saw mill carriage, and the fluid pressure means provided for operating the secondary dogging arm 11 is also used to operate the primary dog so that both the primary and secondary dogs coact in engaging and releasing the log at the top and bottom of the latter.

The secondary dogging arm 11 overcomes the tendency of the log being rolled toward the saw by the constant pressure of the primary dog.

From the foregoing, the construction and operation of the device will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the appended claim.

What is claimed as new is as follows:

A dogging device for saw mills comprising, in combination, a head block for supporting a log thereon and having a log abutting knee, a fixed rearwardly inclined arm attached to and overlying the knee, a pivot pin projecting outwardly at one side of the knee, a dogging arm pivoted on the pin and having one end extending downwardly to underlie the log, a tooth on the lower end of the dogging arm, and fluid pressure actuated means supported between the upper ends of the fixed and pivoted arms to swing the dogging arm upwardly into log engaging position.

References Cited in the file of this patent UNITED STATES PATENTS 392,841 Beard Nov. 13, 1888 936,784 Krebs Oct. 12, 1909 1,712,311 Schnell May 7, 1929 1,840,846 Martin Jan. 12, 1932 

